Environmental Chemistry•2026•DOI: 10.7524/j.issn.0254-6108.2025030501
Coastal areas serve as critical ecological interfaces for the migration of terrestrial microplastics (MPs) into the ocean, and characterizing their pollution is essential for integrated coastal management. This study investigated the occurrence, sources, and ecological risks of MPs in surface waters of nearshore areas and river estuaries around Hainan Island, a typical tropical tourist island. MPs abundance ranged from 316.67 to 1300 n·m−3 in seawater and from 400 to 5416.67 n·m−3 in river water. In seawater, the dominant polymer was polyethylene terephthalate, with fibers being the predominant shape, size class 500–1000 μm, and white/transparent color. In river water, polypropylene-ethylene copolymer dominated, also as fibers, but with size class 100–500 μm and white/transparent color. Seawater MP abundance showed a significant positive correlation with tourist numbers, and distribution across functional areas followed: tourism areas > natural areas > aquaculture areas > residential areas. Multiple correspondence analysis identified household plastic waste, laundry wastewater, aquaculture, and fishery products as primary sources of seawater MPs. Principal component analysis indicated homologous characteristics between seawater and river MPs, suggesting rivers are a major pathway for terrestrial MP transport to coastal zones. Ecological risk assessment revealed low pollution loads, with potential ecological risks moderate for seawater and medium-low for river water. Notably, 15% of seawater sampling sites exhibited polymer risk level Ⅳ, primarily driven by polyacrylonitrile's high biological toxicity. These findings provide a scientific basis for developing MP pollution control strategies in Hainan Island.
Environmental Chemistry•2026•DOI: 10.7524/j.issn.0254-6108.2025030403
Microplastics (MPs) act as vectors for co-migrating antibiotics and heavy metals, forming complex pollution systems with potential joint toxicity. However, the differential adsorption behaviors and underlying mechanisms of MPs toward organic versus inorganic pollutants remain insufficiently understood. This study selected polypropylene (PP) microplastics, a major component of agricultural plastic films, and investigated the adsorption of sulfamethoxazole (SMX) and Cr(VI) onto aged PP under varying environmental conditions. Results demonstrated that aging increased the maximum adsorption capacity by 2–3 times for both pollutants. Notably, aged PP exhibited approximately 30 times higher adsorption capacity for SMX than for Cr(VI). Characterization revealed that aging introduced oxygen-containing functional groups (e.g., carbonyl) on the MP surface, enhancing adsorption. Mechanistic analysis indicated that hydrogen bonding and electrostatic interactions dominated SMX adsorption, while Cr(VI) adsorption was primarily governed by electrostatic interactions and pore-filling. The stronger intermolecular forces for SMX compared to reversible pore-filling for Cr(VI) explained the observed differences. Increasing pH induced electrostatic repulsion, reducing adsorption of both pollutants. High concentrations of Na+ and Mg2+ caused charge shielding, potentially enhancing Cr(VI) adsorption but inhibiting SMX adsorption due to competition for active sites. The presence of organic matter (humic acid) had negligible effects on Cr(VI) adsorption but reduced SMX adsorption, likely due to complexation. These findings elucidate distinct molecular-level pathways for organic versus inorganic pollutant adsorption on aged MPs, highlighting the roles of hydrogen bonding and pore-filling in driving differential behaviors.
Journal of Fuel Chemistry and Technology•2026•DOI: 10.1016/S1872-5813(26)60672-X
Dry reforming of methane (DRM) converts CH4 and CO2 into syngas, offering a route to mitigate greenhouse gases. Ni-based catalysts suffer from sintering and carbon deposition at high temperatures. This work employs MgO-MgAl2O4 composite supports to regulate Ni loading and introduces Ce, La, and Zr as promoters to investigate their effects on DRM activity, structural stability, and surface oxygen species. Optimal Ni loading of 12.5% yields highest CH4 and CO2 conversions. Promoter introduction slightly suppresses low-temperature activity but substantially modifies support local structure and metal-support interface, improving NiO dispersion and increasing surface oxygen vacancies and active oxygen species (Oβ). These changes enhance CO2 adsorption-activation and suppress carbon deposition. After 20 h DRM, Ce-promoted catalyst shows smallest Ni particle growth (6.23→8.07 nm) and lowest carbon deposition, demonstrating superior stability and anti-coking capability. The study elucidates how Ce, La, and Zr enhance sintering and coking resistance via interfacial electronic modulation and improved oxygen storage/release, guiding rational design of stable Ni-based DRM catalysts.